Hydraulic jack



1932- I E. M. PFAUSER 1,873,473

I HYDRAULIC JACK Filed nec. 2o. 1950 s Sheets-Sheet 1 Aug. 23, 1932. E. M. PFAUSER HYDRAULI C JACK 3' Sheets-Sheet 2 Filed Dec. 20. 1930 Aug. 23; 1932.

E. M. PQFAUSEIR 1,873,473

HYDRAULI C JACK Filed Dec. 20. 1950 s Sheets-Sheet 5 I v ,1 is

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Q WW 1% 5 Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE EDWARD M. PFAUSER, F MILWAUKEE-WISCONSIN, ASSIGNOR '10 BLAGKHAWK MANU- I FACT'UT RING COMPANY, OF MILWAUKEE, WISCONSIN HYDRAULIC JACK Application filed December 20, 1980. Serial ms. 508,739.

This invention relates to improvements '111 hydraulic jacks.

One of the objects of the present invention is the provision of what is known as a hy- '5 draulic jack provided with parallel cylinders having pistons operating therein for pumping fluid into the ram cylinder for raising the jack, together with means where- ,by to automatically render one of the pistons;

1 ineffective under a predetermined pressure. Another object of the present invention is the provision of a'hydraulic jack mounted upon traction wheels whereby the same can be easily moved from place to place and supporting a hydraulic operated piston, a

lifting foot with means for operatively connecting the hydraulic piston with the lifting foot, and means for raising the lifting foot rapidly into engagement with the object to be raised and then automatically reducing the pumping of the fluid behind the hydraulic'piston.

A further object of the present invention is the provision of a hydraulic jack including-a supply reservoir for fluid, a hydraulic piston, means for pumping the fluid from. the cylinder into the. piston, together with means manually controlled whereby to return the fluid behind the piston to the reservoir.

A still further object of the invention is the provision of a hydraulic jack mounted upon a small traction frame, and provided with hand operated pumps arranged in substantially parallel relation, together with means whereby one of said pum s is automatically' ineffective under a pre etermined Ream thereof broken away and illustrated in cross section; j

Figure 4 is a sectional view on the line 4-4 of Figure 1;

Figure 5 is a sectional view on the line C 5--5 of Figure 2;

Figure 6 is a sectional view on the line .6-6 of Figure 2;

, Figure 7 is a sectional view on the line 7-7 of Figure 2;

Figure 8 is a section on the line 88 of Figure 5. y

In the construction of my improved jack, I provide two side members 1 and 1' connected at their forward ends by means of the traction axle 2 upon the, ends of which are mounted the traction wheels 3. At the rear of the side members 1 and 1', I provide traction wheels 4. Arranged between the side members is the body 5 of the ram, provided at its lower side with apertured ears 6 mounted upon transverse bolts 7 which extend through the lower edges of the side members.

Extending transversely between the side members above the body of the ram, is a supporting shaft 8, and directly above the supporting shaft 8 and at the top of the raised portions 9 of the side members is a shaft 10 which supports the pivoted plate 11, pivotally connected at 12 to the lifting head 13 adjacent the upper end thereof. It will be noted that the plate 11 is, cut out at its lower end as shown at 14 to provide spaced apertured ears to receive the pivot pin 12. a a

Arranged upon opposite sides of the plate 11 and rockably mounted upon theshaft 8 are the bell cranks 15, each provided with a long arm 16 and a short arm 17'. The long 9 arms 16 normally extend downwardly on an angle, as shown in Figure 3 and are pivotally connected at 17 to the lifting foot 13 adjacent the lower end thereof. The short 5 arms 17 of the bell cranks are pivotally con- 9 nected with the links 18 which are in turn pivotally attached to the head 19 on the ram piston 20. The piston 20 is mounted for reciprocating mo Within a cylinder .100

The ram housing 5 is provided with an opening at its forward end and removably mounted within this opening is a sleeve 22, in the inner end of which supports one end of the cylinder 21, while the outer end supports suitable packing 23 to prevent leakage around the piston. The inner end of cylinder 21 is threaded into a block 24 within the. ram housing, as shown in Figure 4. At this point, I wish to call-attention to the fact that the shaft 8 is supported at its central portion in a bearing '25 on the top of the ram housing, as shown in Figures 1 and 2. V

Directly beneath the cylinder 21 is a fluid reservoir 26 and arranged upon each side of the reservoir 26 are the cylinders27 and 28. Mounted for reciprocating movement inthe cylinder 27 is a piston 29 having a central bore 30 with a threaded counter bore adapted to receive the reduced threaded end 31 of the rod 32. The piston 29 is provided at its removable end with suitable packing which is retained in place'by means of thecap sleeve 33. In the end of the cylinder 27 opposite the cap sleeve 33 is a block 34 provided with a central aperture 35 normally closed by means of a ball-valve 36. The aperture 35 communicates with a chamber 37 within the cylinder 27 between the block 34 r sure 41 is a stop member 43 arranged at the outer end of rod 32. Loosely mounted upon the rod 32 between the stops 41 and 43 IS the lower end of arm 44, mounted upon stub. shaft 45. The head of the arm which is mounted on the shaft 45 is provided with a cut out portion 46 adapted to receive an offset part 47 on collar 48.

The collar 48 is carried by yoke- 49 con nected directly to handle 50. It will be noted in Figure 1 that the stub shaft 45 is supported in a suitable bearing 51 in the side member 1. Mounted-for reciprocating movement within the cylinder 28 is a piston 52 provided with suitable packing'53 at one end of the cylinder 28, and arranged within the other end of the cylinder is a removable block 54 having an aperture therethrough, as shown at 55 adapted to be vclosed against passage in one. direction by means of a ball valve 56. The aperture 55 communicates with a chamber 57 between the closure plug 58 and block 54., The chamber 57 communicates with the reservoir 26 through passage 59.

The outer end of the piston 52 is provided with a head 60, rece ssed as shown at 61, and

is an adjusting screw, 65.

at one side of the recess, the head and a portion of the cylinder are provided with a bore 62 in which a headed pin 63 is mounted. The head is provided directly opposite the bore 62 with a threaded aperture 64 and adjustably mounted in the threaded aperture 64 .Arranged within the recess 61 and positioned between the head of the pin 63 and adjusting screw 65 is a rounded head 66 of the rockable arm 67. The arm 67 is provided at its upper end with a collar 68 mounted on I stub shaft 69, which'is in turn mounted in a bearing 70 carried by the side member 1. The collar 68 is provided with a cutout part 71 adapted to receive an offset portion 72 on collar 73, carried by the yoke 49. From this description, it will be apparent that pistons 29 and 52 will be operated simultaneously through actuation of the handle 50.

Formed in the bottom portion of the reservoir 26 is a conduit 74' which communicates With a similar conduit 75 in one end of the reservoir that leadsinto a chamber 76 in the block 24. The outer end of this chamber is closed by means of a screw plug 77. Arranged within the chamber 76 at its inner end isa block 78 havinga passage therethrough closed against fluid in one direction by means of a ball valve 79. The inner end of chamber 76 communicates with an expansionchamber 80 at the end of cylinder 21,

the passageway 81 forming communication between chambers 76 and 80.

A threaded plug 82 closes the outer end of conduit 74 and a similar plug 82 closes the lower end of conduit 75 whereby these conduits may be readily cleaned of foreign material by removing the plugs 82 and 82' respectively. Leading back into the reservoir 26 is a passageway 83 which extends through block 24 and communicates with chamber 80 by a lateral passage 84. A needle valve 8 5 is mounted in block 24 and connected up with rod 86 whichextends through the handle 50. The outer'end of the rod 86 carries a head 87 rotatable independent of the handle 50 whereby passage 84 may be opened and closed by the operator.

Communication between the cylinder 27 and conduit 74 is established by means of a lateral passage 88, and communication between the cylinder 28 and conduit 74 is established' by means of a lateral passage 89. Thus, the fluid pumped from the reservo1r 26 into either one of the cylinders 27 and 28 will be directed into the conduit 74 up through conduit 75 and into cylinder 21 for reciprocating the ram piston 20.

In theoperation of my improved hydraulic jack, attention is directed to the fact that the valve is closed and handle 50 is actuated to simultaneously reciprocate pistons 29 and 2 in their respective cylinders. The

-when it is desired to raise the lifting head 13, I

lifting head 13 being properly positioned under the object to be raised, will be rapidly llfted due to the fact that both pistons 29 and 52 will operate simultaneously until the head 13 engages the object, at which time the fluid pressure in front of piston 29 will overcome the tension of spring 40 and cause the closure stop 41 and tube 42 to reciprocate on rod 32 agalnst the tension of the spring, thus leaving only piston 52, operating to pump the fluid from the reservoir to the cylinder 21 behind piston 20. As piston moves outwardly, it rocks the bell cranks 15, the long I arms of which will raise the lifting head 13 plate 11 holding the lifting head in proper position so that it will be raised in a vertical plane.

. is the provision of a hydraulic jack including parallel pump members adapted to be simultaneously operated' in the initial raising of the lifting head, but as soon as pressure is brought to bear upon the lifting head, one of the pumps Will be automatically rendered ineffective.

though the Thus, the pressure will be continued by the operation of the smaller cylinder and piston, slowly raising the head in its operation. By providing such a construction, it will save considerable time in bringing the lifting head into contact with'the object to be raised and efiect a quicker operation of the jack.

By providing a jack of this character with suitable traction means, the same can be quickly moved about, and due to the lower position of the lifting head, the same can be inserted beneath an object very close to the surface on which the jack is mounted and even object to be lifted is disposed at a considerable height above the head, the head can be quickly raised into contact with the object through the actuation of both of the pumps, and the raising can be continued through the, operation of one of the pumps. The construction of the jack is comparatively simple and it is believed that it can be manu- I factured and placed on the market at a very low cost. I v

While I have shown and described the preferred embodiment of my invention, it'will be apparent from the foregoing that slight changes may be made in the construction invention into practice without departing from the spirit of the same or the scope of the appended claims. 7

through the passage 84 and passage 83,

.the frame,

; rockable on the stub shafts, a rockable lever oneach shaft operated by the adjacent arm of the yoke, and means operatively connecting the levers independently of one another to a piston.

2. In a vehicle frame, a movable load engaging member mounted on the frame, a ram mounted on the frame operatively connected to said load engaging member, a pair of pump units for actuating the ram, each including a piston, a

pair of transversely aligned stub shafts on an operating handle having a yoke on its inner end with the arms thereof rockable on the stub shafts, a rockable lever on each stub shaft operated by the adjacent arm of the yoke, and means operatively connecting the levers independently of one another. to a piston, one of said means rendering one pump unit ineffective when a predetermined pressure is created.

3. In a vehicle "lifting jack, a Wheeled frame, the frame, a ram mounted on the frame operatively connected to said load engaging mem- I units mounted upon the frame for actuating the ram, each of said pump units including a piston, a piston rod connected with one of said pistons, a spring on said piston rod, a collar arranged on the piston rod for sliding movement against the ber, a pair of pump lifting jack, a wheeled.

a load engagingmember mounted on lifting jack, a wheeled I each including a piston,

tension of said spring, a pair of transversely aligned stub shafts on the frame, ing handle having a yoke on its inner end with the arms thereof rocka'bly mounted on the stub shafts, a rockable lever on each stub shaft operated yoke, one of said levers being slidably mounted on the piston rod and engaging the sliding collar, and means operatively connecting the other lever to the piston.

4:. In a power mechanism, a frame, a load engaging member mounted on the frame, a ram mounted on the frame operatively connected to said load engaging member, a pair of pump units for-actuating the ram, each including a piston, a pair of transversely aligned stub shafts on the frame, an operating handle having a yoke on its inner end, the arms ofthe yoke being rockable on the stub shafts, a rockable lever on each shaft operated by independently of one another to a piston.

5. In a power mechanism, a base, a hyan operatby the adjacent arm'of'the.

the adjacent arm of the yoke, and means operatively connecting the levers means operatively connecting the levers indraulic ram mounted on the base, a pair of pump unitsifor a'ctuatin the ram, each including a piston a pair o transversely alined stub shafts carried on the base, an operating handle having a yoke on its inner end, the

arms of the yoke being journalled on the stub shafts, a rockable lever on each shaft actuated by the adjacent arm of the yoke, and

dependent of one another-to a piston.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee and State of Wisconsin.

EDWARD M. PF AUSER. 

